Fluid-entangled nonwoven fabric

ABSTRACT

A nonwoven fabric comprising a plurality of layers of generally parallel fiber-containing strands, the strands of one of said layers being disposed at varying inclinations with respect to the strands of an adjacent layer along the length of the fabric, and the fibers of said strands being entangled with fibers of adjacent strands both in the same layer and in a different layer.

nited States Patent 1111 3,623,935

[72] Inventors William T. Allman, Jr. [56] References Cited Charlotte,N. C.; UNITED STATES PATENTS James i Charm, William 3,235,935 2/1966Daruwalla 161/154 x 3,055,080 9/1962 Claussen et al. 28/1 .4 1 pp N9637,654 3,129,466 4/1964 LHommedieu 19 161 x 1 Filed 4, 1967 3,193,4367/1965 Kalwaites 16 H78 1 Continuation nfSer- 5 6,858, D 28, 3,391,0487/1968 Dyer et al. 161 1 54 x 1965, N 3,3 7,074 3,422,510 1/1969Livingston et a]. 16 1/72 x [45] Patented Nov. 30, 197i [7 3] AssigneeCelanese Corporation New York, N.Y.

Primary E.raminer- Robert F. Burnett Assistant Examiner-Roger L. MayA!!urneys--L. Horn, S. D. Murphy and Robert J. Blanke [54]FLUIDENTANGLED NONWOVEN FABRIC ABSTRACT: A nonwoven fabric comprising aplurality of 2 Claims 5 Dram" layers of generally parallelfiber-containing strands. the

[52] US. Cl 161/57, strands of one of said layers being disposed atvarying inc|ina 28/722, 16l/72 lions with respect to the strands of anadjacent layer along the [Si] lint. Cl B32!) 5/12 length of the fabric,and the fibers of said strands being entan- [50] Field of Search 161/72,80, gled with fibers of adjacent strands both in the same layer and I42,154, 169, 57, 78, 55; 28/722, L4; l9/l6l in a different layer.

PATENIED mlvao Ian sum 1 nr 2 INVENTOR WILLIAM T. ALLMAN,JR WILLIAM ABURN,JR JAMES H.WINGER BY M ATTORNEY PATENTED unvao Ian SHEU 2 BF 2 5 PUF a mvsmon WILLIAM T. ALLMAN,JR.

n m w n R W%/ WW/ W M MS E um WJ/ FLUID-ENTANGLED NONWOVEN FABRIC Thisinvention which is a divisional application of copending application,Ser. No. 516,858 filed Dec. 28, 1965 now U.S. Pat. No. 3,357,074, issuedDec. 12, I967, relates to the manufacture of nonwoven fabrics.

It is concerned particularly with a method of and apparatus formanipulating fiber-containing strands so as to dispose the strands atvarying inclinations with respect to the length of a sheet formed byentangling fibers of adjacent ones or groups of the strands. The novelfabric so produced has a number of advantageous characteristics.

Processes for obtaining nonwoven fabrics in the form of assemblies ofentangled fibers have been known. A process of particular interest isdisclosed in US. Pat. No. 3,055,080, granted to Claussen et al. on Sept.25, 1962. In accordance with the disclosure of this patent, a pluralityof yarns in the form of a flat sheet are fed continuously to fluid jetmeans having a slit-shaped nozzle. A jet of turbulent fiber plasticizingfluid acts upon the strands tocrimp the individual fibers of the yarnsand to entangle the fibers so as to form a cohesive sheetlike structure.

The present invention also is concerned with fluid entangling techniquesfor making nonwoven fabrics. It is an object of the invention to providea method of and apparatus for improving the widthwise strengthcharacteristics of fabric produced by fluid weaving or entanglingprocesses. Another object of the invention is to provide a method andapparatus which may be used to achieve pattern effects in fluidwovenfabrics.

In accordance with anembodiment of the invention, a plurality offiber-containing strands in sheet form are fed at a first rate towardfluid jet means and shifted back and forth laterally prior to theirentrance into the fluid jet means to dispose the strands at varyingangles with respect to the longitudinal axis of the fiber passagewaythrough the fluid jet means. While the strands are within the fiberpassageway of the fluid jet means they are contacted by a high-velocityfluid stream that serves to entangle fibers from adjacent strands insuch a manner as to provide the sheet with structural integrity. Thesheet is engaged by feeding means again after it leaves the fluid jetmeans, but the second feeding means operates to advance the sheet at arate slower than that to which the strands were fed into the fluid jetmeans. That is to say, the linear rate of input is greater than thelinear rate of output, so as to allow for the fonnation of loops inindividual fibers and for inclination of the various strands relative tothe lengthwise direction of the sheet.

It is contemplated that a plurality of groups of strands, each in sheetform, may be fed simultaneously to the fluid jet means. When this isdone, it is preferred that the individual sheets be oscillated laterallyout of phase with each other and that they enter the fluid jet means ingenerally superimposed relation. Fibers from the individual sheetsbecome entangled not only with fibers from adjacent strands in the samesheet,

. but with fibers from strands in other sheets, producing a unitaryassembly.

A more complete understanding of the invention may be gained from aconsideration of the following detailed description, taken in connectionwith the accompanying drawings in which:

FIG. 1 is a diagrammatic view of an apparatus setup suitable for thepractice of the invention;

FIG. 2 is a longitudinal cross-sectional view through a fluid jetstructure of the type employed in the apparatus setup depicted in FIG.1;

F IG. 3 is a transverse cross-sectional view taken along the line 33 inFIG. 2 and illustrating the entrance end portion of the fluid jet means;

FIG. 4 is an elevational view of an oscillatable reed constructionsuitable for use in the apparatus set up depicted in FIG. 1; and

FIG. 5 is a somewhat schematic view illustrating the appearance of theface of a fabric formed through the use of the apparatus setup of FIG.1.

In FIG. 1, the reference numeral 2 designates a conventional strandsupply, such as a creel or one or more warp beams. A plurality offiber-containing strands 4, preferably in the form of zero twist yarnsmade up of continuous filaments, are withdrawn from the yarn supply 2 byfeed means, here shown as a single pair of feed rolls 6 and 8. Normally,it will be found preferably to pass the strands 4 over a strand guidingand tensioning member 10 disposed between the strand supply 2 and thefeed rolls 6 and 8. Also, it is desirable ordinarily to pass groups ofthe strands 4 through strand-separating means 12 and 14, such as reedsor eye boards, as the strands travel toward the feed rolls 6 and 8. Thestrands passing through the reed 12 have been designated 4a and thestrands passing through the reed 14 have been designated 4b. If desired,separate sets of feed roll pairs may be provided for receiving the twogroups 40 and 4 b and these may be rotated at the same or differentrates.

After being acted upon by the feed means, the strands of the group 4apass through an oscillatable reed unit 16a and the stands of the group4b pass through an oscillatable reed unit 16b. Either or both of thereed units 16a and 16b may be shifted back and forth in the widthwisedirection of the advancing strands as the strands pass through thereeds.

The strands of groups 4a and 4b come together again at the entrance endof a fluid jet means 18. In this zone, the two strand groups will be inthe form of superimposed sheets. They pass together in this form throughthe fluid jet means where they are acted upon by high-velocity fluid toentangle the fibers of the various strands and to produce a cohesivesheet or fabric structure. The fabric structure issuing from the fluidjet means has been designated 4c in FIG. 1.

The fabric 40 passes over guide means 20 and is fed away by feed rolls22 and 24, the surface speed of which is substantially less than thesurface speed of the input feed rolls 6 and 8. This difference in thelinear rates of advance in the two parts of the system makes it possiblefor the fibers to assume angular positions with respect to the length ofthe fabric 40. Individual fibers extend laterally in loop or crimp formto interlock with fibers from other strands, and the strands as suchhave wavy configurations along the length of the fabric 4c. The wavyconfiguration of the strands is suggested in FIG. 5. From this view, itwill be observed that novel pattern effects have been achieved. Also,the lateral extend of the strands in various portions of the fabricserves to improve the widthwise strength characteristics of the fabric.The lateral spacing of the strands making up the fabric may be varied inorder to produce different effects and structural properties. In theinterests of clarity, the strands 4a and the strands 4b have been shownin FIG. 5 as being rather widely spaced apart in a lateral direction,but it will be understood that greater fiber densities are possible andoften desirable.

The construction of the jet means 18 will be apparent from aconsideration of FIGS. 2 and 3. The jet means illustrated in FIG. 2 ismade up of a body 26, an inlet end unit 28, and an outlet end unit 30. Ayarn passageway 32 formed internally of the units 28 and 30 is elongatedin the transverse direction as suggested in FIG. 3 to permit the groupsof strands 4a and 4b to remain generally in sheet form as they passthrough the jet means 18.

Air or some other suitable fluid under pressure is introduced into thejet means through openings 34 and 36. The proximate surfaces 38 and 40at the adjacent ends of the inlet and outlet units 28 and 30 are spacedapart from each other to permit the fluid to pass downwardly from theinlet ports 34 and 36 into contact with the fiber-containing strands andout the lower outlet end of the yarn passageway 32. The flow velocity ofthe air is high, and as a result the fibers making up the strands arelooped and otherwise distorted to produce an entangling effect thatgives the fabric the desired cohesive character.

Although the fluid flow through the outlet end of the strand passageway32 has a component in the direction of the longitudinal axis of thestrand passageway, the several strands making up the groups 4a and 4b donot straighten under the influence of this flow. It has been found thatthe entanglement of the fibers is sufficient to lock the strands inangular positions corresponding generally to the angularity resultingfrom the lateral oscillations imparted to the strands by the reeds 16aand 16b just prior to their entrance into the strand passageway 32.

In connection with the oscillation of the strands back and forth in thewidthwise direction, particular attention is invited to FIG. 4 of thedrawings. In this view, a reed 16b, and means for oscillating it, areshown. The reed 16b is made up of a frame 38 carrying separator members40 that serve to space individual ones or small groups of the strands4b. In FIG. 4, varying numbers of strands 4b have been shown in thespaces between adjacent ones of the separator members 40 to indicatethat the exact number is not a matter of critical importance. The frame38 includes laterally extending end members 42 mounted for slidingmovement 50 normally urges the reed 16b to the right as viewed in FIG.4, but pattern means 52 may overcome the bias of the spring means 50 tomove the reed 16b to the left.

The illustrated pattern means 52 is very simple in construction, beingmade up of a driven shaft 54 having mounted thereon an eccentric 56. Asthe shaft 54 is rotated, the eccentric 56 cams the reed 16b to the leftand then recedes to allow the spring means 50 to shift the reed 16b tothe right. Various forms of pattern means are known to the art, and itcontemplated that the selection of particular pattern means will bebased on structural considerations and also on the intricacy of thedesired patterning. The details of the pattern means form no part of thepresent invention.

The appearance effects achieved as a consequence of the wavydispositions of the strands and the splayed arrangements of individualfibers in the fabrics produced in accordance with this invention may bevaried somewhat through selection of various strand materials for use inthe process. The strands may be in the form of tows, silvers, yarns orother assemblies, of either natural or synthetic fibers. The fibersand/or strands used in any given fabric may have the same or differentcolor, luster, and/or denier characteristics.

Although a single embodiment of the invention has been illustrated inthe drawings, it will be understood that this embodiment is exemplaryonly. It is intended that the scope of the invention be ascertained fromthe following claims.

1. A nonwoven fabric comprising a plurality of layers of generallyparallel fiber-containing strands, the strands of one of said layersbeing disposed at varying inclinations with respect to the strands ofthe adjacent layer along the length of the fabric, the strands of eachof said layers having wavy configurations along the length of the fabricwith the waves of one layer being out of phase with the waves of anadjacent layer, the fibers of said strands having angular positions withrespect to the length of said fabric, said fibers extending laterally inloop or crimp form and being entangled with fibers of adjacent strandsboth in the same layer and in a different layer.

2. A nonwoven fabric as defined in claim .1 wherein said strands arezero twist yarns of continuous filaments, the individual fibers of saidstrands interlocking with fibers from other strands.

2. A nonwoven fabric as defined in claim 1 wherein said strands are zerotwist yarns of continuous filaments, the individual fibers of saidstrands interlocking with fibers from other strands.